March 20, 2023: Pipeline Replacement and Nitrogen Purging Project for Defective Welds on the Zhonggui Natural Gas Pipeline

On March 20, 2023, our company undertook the critical task of nitrogen purging for the replacement of pipeline sections at the circumferential weld crack defect along the Zhonggui Line, specifically at K797+807m. This project presented significant challenges, including the confined space around Valve Station No. 35 and the need to coordinate two simultaneous operations. Through two thorough on-site inspections and extensive discussions involving multiple stakeholders, our team successfully addressed obstacles such as limited workspace and complex construction scheduling. From March 20 to 22, with guidance and support from Southwest Pipeline Company, we meticulously executed two nitrogen purging operations: the first took just 2.3 hours (compared to the original estimate of 3.8 hours), while the second was completed in 1.6 hours (vs. the planned 2.8 hours). Overall, productivity improved by 169%, ensuring that Valve Station No. 34 met the stringent oxygen content requirement of 0.3%. As a result, we earned high praise from both the client and the local management authorities.